I'm opposed to violence, however I define it differently to how the state does. One example of violence that wouldn't be considered by the state to be violence is calling the cops.
Violence is a hierarchy and as soon as you understand that, the more you understand it as a meaningless term.
I think that violence can be adequately defined as "the instigation of aggression/harm against peaceful beings." Hierarchy is not strictly required for this.
That assumes that it is a neutral act and an act based souly on who hit first. It leads to some serious moral consequences to work based on the schoolyard politics of, "But miiiissss, he hit me first"